﻿using System;
using System.Text.RegularExpressions;

namespace FW
{
    public static class HtmlRemoval
    {
        /// <summary>
        /// Remove HTML from string with Regex.
        /// </summary>
        public static string StripTagsRegex(string source)
        {
            return Regex.Replace(source, "<.*?>", string.Empty);
        }

        /// <summary>
        /// Compiled regular expression for performance.
        /// </summary>
        static Regex _htmlRegex = new Regex("<.*?>", RegexOptions.Compiled);

        /// <summary>
        /// Remove HTML from string with compiled Regex.
        /// </summary>
        public static string StripTagsRegexCompiled(string source)
        {
            return _htmlRegex.Replace(source, string.Empty);
        }

        /// <summary>
        /// Remove HTML tags from string using char array.
        /// </summary>
        public static string StripTagsCharArray(string source)
        {
            char[] array = new char[source.Length];
            int arrayIndex = 0;
            bool inside = false;

            for (int i = 0; i < source.Length; i++)
            {
                char let = source[i];
                if (let == '<')
                {
                    inside = true;
                    continue;
                }
                if (let == '>')
                {
                    inside = false;
                    continue;
                }
                if (!inside)
                {
                    array[arrayIndex] = let;
                    arrayIndex++;
                }
            }
            return new string(array, 0, arrayIndex);
        }

        public static string SecureQueryString(string TexttoValidate)
        {
            try
            {
                string TextVal;

                TextVal = TexttoValidate;

                //Build an array of characters that need to be filter.
                string[] strDirtyQueryString = { "xp_", "<", ">", "script", "iframe", "delete", "drop", "exec" }; // ";", "--", 

                //Loop through all items in the array
                foreach (string item in strDirtyQueryString)
                {
                    if (TextVal.ToLower().IndexOf(item) != -1)
                    {
                        throw (new Exception("SQLINJECTION"));
                        //PageRedirect(1);//Redirect to page not found.
                        break;
                    }
                }

                return TextVal;
            }
            catch (Exception ex)
            {
                throw (ex);
            }
        }
    }
}
